In a printer configured to perform a printing operation for a recording sheet, there has been proposed a technology of transmitting/receiving print data for printing by wireless communication. In this technology, the printer acquires print data from a PC, which is connected to a relay apparatus (for example, an access point) of wireless LAN, by wireless communication through the relay apparatus of the wireless LAN that covers a using place of the printer, and executes a printing operation based on the received print data.